/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.gds.kcore;

import org.neo4j.gds.collections.ha.HugeLongArray;

import java.util.function.LongUnaryOperator;

final class NodeProvider {

    private  final LongUnaryOperator nodeOperator;
    private final long size;

    private NodeProvider(long size, LongUnaryOperator operator){
            this.size  = size;
            this.nodeOperator = operator;

    }

    long node(long indexId){
        return nodeOperator.applyAsLong(indexId);
    }

    long size(){
        return size;
    }

    static NodeProvider fullNodeProvider(long size){
        return new NodeProvider(size, LongUnaryOperator.identity());
    }

    static NodeProvider reducedNodeProvider(long size, HugeLongArray nodeOrder){
        return new NodeProvider(size, nodeOrder::get);
    }

}


